naphthalene

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A white crystalline aromatic compound, C₁₀H₈, derived from coal tar or petroleum and used in manufacturing dyes, moth repellents, and explosives and as a solvent.

from The Century Dictionary.

• noun A benzene hydrocarbon (C₁₀H₈) usually prepared from coal-tar.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) A white crystalline aromatic hydrocarbon, C10H8, analogous to benzene, and obtained by the distillation of certain bituminous materials, such as the heavy oil of coal tar. It is the type and basis of a large number of derivatives among organic compounds. Formerly called also naphthaline.
• noun (Chem.) a dyestuff obtained from certain diazo derivatives of naphthylamine, and called also magdala red.
• noun (Chem.) a yellow dyestuff obtained from certain nitro derivatives of naphthol.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A white crystalline hydrocarbon manufactured from coal tar; used in mothballs.
• noun organic chemistry An aromatic bicyclic hydrocarbon, C10H8; an acene containing two fused benzene rings.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a white crystalline strong-smelling hydrocarbon made from coal tar or petroleum and used in organic synthesis and as a fumigant in mothballs